Telephone-receiver.



L. W. CARROLL. v

TELEPHONE RECEIVER.

APPLICATION FILED 0011.24, 1910.

1,034,200. Patented July 30,1912.

2 SHEETS-SHEET 1.

Zz... l 1%7/ gw 'L. W. CARROLL.

TELEPHONE RECEIVER.

APPLICATION FILED 00T.z4,1910.

1,034,200, Patented July 30, 1912.

2 SHEETS-SHEET 2.

UNITED STATES `PATENT OFFICE.

' Louis w. cannoni., or nrvnnsrnn, Immers.

speemaon of Letten Patent.

Patented Jpiy 30,1912.

applicati@ ined october 24,1910. sami nu. '$83,997.

To all fw/wm t may concem: Be it known that'I, Louis W. CARROLL, 'a citizen of the United States of America, and resident of Riverside, county of Cook', and State ofl Illinois, have invented certain new and useful Improvements in Telephone-Re" ceivers, vof which the following is a s eciiication, and which are illustrated in t e accompanying drawings, forming a part thereof.

The invention relates to telephone receivers,'and"has for its objectV to increase the eiliciency of instruments of this kind.

In its broadest aspect, the invention contemplates the use of a dia hragm, and an actuating magnet located 1n front of the diaphragm or lupon that side of-the diaphragm at which provision is also made for y net coils of the the emission of the sound produced by the vibration of the diaphragm. In carrying out the invention kI prefer, however, to use a. pair of actuating magnets, one located upon each side of the diaphragm, the coils of the two magnets being so connected that when the attractive effect of one of the magnets is Iincreased vthat of the 'other is reduced. n

A detail of the invention provides a magnet for'use in front of the diaphragm, having a central aperture forthe emission of sound. y

In the accompanying drawings, Figure l is a detail central sectional view of one form i of telephone receiver embodying the improvements 2 is a sectional view taken on the broken line 2-2 of Fig. 1; Fig. 3 is a diagram illustrating the manner of winding and connecting the magnet coils of the structure illustrated in Figs. 1 and 2; Fig. ll-is similar to Fig. 1 but shows a different embodiment of' the invention;Fig. 5 is a perspective view showing the actuating ma ets employed in the form of constructionlllustrated in Fig. 4; and Fig. 6 is a diagram illustrating the method of winding and connecting the magstructure illustrated in Figs. 4 and 5.

In practice the operative parts of the receiver may be inclosed withm a shell comprising a body portion or hand-piece 10, and an ear-piece or cap 11, both of which -are shown as resembling in external appearance the corresponding parts of telephone receivers now in use, except that the ear-piece 11 has an end opening 12 of somewhat nection 13. As shown,

provided by the invention; Fig.

larger diameter than the corresponding opening in receiver shells vheretofore employedr {"Tlitwo members 10, 11,' of the shell preferably have a screw-threadedfcon- A oppositely-facing shoulders .14 and 15 are members 10, 11, and the operative .parts of the receiver are clamped between these shoulders when the members ofxthe shell.

are sere ed together.l A soft iron dia-V phragm-1 ofusual construction is ,employed 'as the sound producing medium. l

In the form 'of construction illustrated in Figs. 1, 2 and 3. ofthe drawings, permanent -steel magnets' 17 and 18-are employed. As

shown, each of thesel magnets takes the' forml of an annulus or disk having a central opening'19. The disl a re preferably substantially coextensive Vwith the"'diaphragm 16, and, both of themare so ma etized. as Ato have one pole upon the periphery of the disk and the other pole upon the inner margin of the disk about the central opening 19. The two disks or magnets 17, 18, are used upon opposite sides of the diaphragm 16, and they are oppositely magnetized in order that if the disk17 esente a south pole adjacent -thencenter o phragm, the disk 18 will ,present a north pole upon thel oppositeside .of the diaphragm in line witlr'the south pole of the disk17.v

The disks 17, 18, are separated from thediaphragm '16 on each side by a spacing ring, as 20 and 21., preferably made-of soft iron, and each has -a marginal ange Vor bead 22 upon its inside facewhereby the margins of the diaphragm" 16 may be clamped between the spacing rings 20 and 21, while still leaving the diaphragm 16 free to vibratefor nearly its whole extent.

A soft iron tubeV or nipple 23 is fitted within the central opening 19 of each of the disks 17 18.l These nipples] project inwardly from the face of the disks toward the diaphragm 16. Magnet coils 24, 25, are wound about the inwardly-projecting ends of the tubes or nipples 23. These coils are y preferably connected' by a wire 26, extending beyond the margins of the diaphragm 16, as by being laid in rooves 27, 28, formed radially in the faces o the spacing rings 20 and 21, and the coils are oppositely wound, as shown in diagram in Fig. 3. The terminals 29, 30, of thecoils 24, 25, are laid into These spacing rings are provided on the,

the dia- 38, is laid upon the shoulder 14 to form a cushioned seat for the disk 17, and the several parts are then clamped together upon this seat by'screwing the ear-piece 11 onto the body portion or" handle 10 of the shell.

In' the form of constructionV illustrated in Figs. 4, 5 and 6 of the drawings, no permanent magnets are employed, but 1n lieu thereof soft iron disks 39, 40, adapted to be continuously magnetized by a direct current,

are yused. As in the form of construction illustrated in Figs. 1, 2 and 3 of the drawings, the disks 39 and 40 are-each substantially coextensive with the diaphragm 16, and they are located upon opposite sides of the diaphragm. Each of the disks has a central opening 41, and about this opening the 'disks are so formedas to provide an inwardly-facing tubular shank or stem 43 at the center of each disk, and an annular groove or channel 42 about the stem 43. At the margins of the disks 39, 40, there are instanding beads or anges 44, 45, for engagingthe opposite faces of the diaphragm 16 adjacent its margins. l

For continuously magnetizin the disks 39, 40, whereby their instanding tubular stems 43,will. present opposite poles to the diaphragm 16, magnet coils 46, 47 each preferably consisting of a comparatively large number of turns of relatively coarse wire, are laid into the annular grooves or channels 42. Preferably these coils fill the channels 42 fo'r the greater portion of their depth, but leave the tips of the tubular stems 43 uncovered for receiving a second coil, as 48, 49. The latter coils each preferably consist of a comparatively small number of turns of relativel lfine wire.

The coils 46, 4 ,and the coils 48, 49, are connectedas by means of wires 50 and 51, extending over the margins of the diaphragm 16, as by being laid into grooves or notches 52, 53, in the disks 39 and 40. As most clearly shown in Fig. 6 of the drawings, the coils 46 and 47 are wound in the same direction, but the coils 48, 49; are preferably 4oppositely wound, the coil 48, as shown, being wound in the same direction as the coils 46 and 47 The coils 46 and 47, and the coils 48 and 49, are preferably connected in parallel or branch circuits. This is lconveniently effected by connecting the terminals, as 54 and 55, of the coils 46 and 47 with the respective terminals, as 56 and 57, of the coils 48 and 49, as shown at the junction points 58 and 59.

Binding posts 62 and 63 are preferably employed for receiving the leading-in wires 36 and 37. As inthe construction shown in Fig. 1 of the drawings, the-binding posts are conveniently mounted upon a lug 64, formed upon thel inside wall cf the handle portion 10 of the shell. Connections 60 and 61 lead from the junction points 58 and 59 to ythese binding posts 62 and 63, respectively.

When the parts are assembled the margins of the diaphragm 16 are clamped between the margins of the disks or magnets 39 and 40, and all of the parts are firmly bound together by screwing the cap portion 11 of the shell onto the handle or body portion 10.

In both of the forms Iof construction illustrated, the central portion ofthe disk -or magnet, as 18 andv40, located in front of the dia hragm 16, is exposed through the cen tra opening 12 of the cap 11, thereby permittin the sounds produced by the vibration o the diaphragm 16 to escape through the tubular members 23 and 43. By locating magnets of opposite polarity uponv the two sides of the dlaphragm, the diaphragm is` lthe diaphragm is disturbed, and the diaphragm is accordingly vibrated.

The arrangement is such that when the attractive force of one of the magnet poles, as 17 and 39, is augmented, the attractive force of the other magnetic pole, as 18 and 40, is diminished. By means of this construction a very'slight deviation of current in the magnet coils, as 24 and-25, or 48 and 49, is sufficient to cause aconsiderable deection of the diaphragm 16. The deliection of the diaphragm 16 is further enhanced by the excitation of magnetic lines of force in the diaphragm itself, because of the location of the oppositely wound coils 24, 25, or 48, 49, upon opposite sides of the diaphragm.

. Because of the relatively'high resistance of the coils 48, 49, provided in the form of construction illustrated in Figs. 4, 5 and 6 of the drawings, a continuous direct current will flow principally through the coils 46,

47. On the other hand, an undulatin cur-A rent, such as that produced by talking into a telephone transmitter of ordinary form, will flow principally through the coils 48 and 49, because of the relative `impedance of the -coils 46 and 47 While the operative parts of the receiver are shown as being inclosed in a shell of about the size and shape of that used for telephone receivers of the form now in very common use, it 'is obvious that because of the compact arrangement of the actuating magnets about the diaphragm the parts may be inclosed within a. shell of muclr': less length', if desired. Furthermore, in the forms of construction described there. will be no changes in the distance between thev vmagnets and the diaphragm produced by unequal expansion and contraction between the parts of the shell'and the metal parts of the apparatus when subjected t'o changes in temperature, as has been the case, with many telephone receivers heretofore used. While the magnet coils 48, 49, in the for of constructionillustratedl in Figs. 4, 5 and 6 of the drawings are of relatively high resistance, they will, of course, receive some` of the direct current. In order that the magnetic eHect of the two magnetpoles located on opposite sides of the diaphragm 16 may be balanced 'when only direct current is being supplied to the receiver, the coil 46 1s, therefore, preferably made of 'a l'argerr-y number of turns than the. coil 47, for the reason that the coils 46 and 48 are oppositely wound, whereas theA coils 47 ,and 49 are 'similarly"w0und. lTo prevent induced currents traversing the poles, as 23 and 4310i the magnets, circumferentially, these are preferably divided into segments, as by saw kerfs 65 and 66.

I claim as m "invention- V p 1. In a telep one receiver, in combination, a diaphragm, a soft iron cup facing the diaphragm and substantially coextensive with it, a .soft iron stem projecting centrally from the bottom of the cup toward the dia-v phragm, a coil of low resistance Aand high impedance surroundin the greater portion of the stem except its t1p, and a coil of high resistance and low impedance surrounding the tip of the stem, the two coils being connected in. parallel. y

2. In a telephone receiver, in combination, a diaphragm, a soft iron cup facing the diaphragm upon each side, each of said cups being substantially coextensive with the diaphragm and the two cups being magnetically connected at their iron tubular stem projecting centrally from the bottom of each cup toward the diaphragm, a coil of low resistance and high impedance surrounding the reater Aportion of each tubular stem except its tip, the two coils being connected and similarly wound, and a coil of low impedance and high resistance surrounding the tip of each stem, the two last-named coils being connected peripheries, a soft- 'positely wound.

and being reversely wound, and the two lastv in parallel with pedance filling the bottom portion of thetrough, and a coil of high resistance and low impedance filling the upper portion of the trough, the two coils being connected in parallel.

4. In a telephone receiver, in combination, a diaphragm, an annular trough-shaped piece of soft iron facing the diaphragm uponj each side, a coil of low resistance and high'impedance illing the bottom portion of each'trough, the two coils being connected and lsimilarly wound, a coil of high resistance and low impedancefilling the upper portion of each trough,y the two last-named coils being connected and reversely wound, and thetwo first-named coils being in'a par- 4 allel circuit with the two last-named coils.

.. 5. In a telephone receiver, in combination, a diaphragm, an actuating magnet having a soft iron core and two energizlng coils connected in parallel relation located on each side of the diaphragm, the two coils of one of the magnets being similarly wound and the two coils of the other magnet being oppositely wound, andthe several coils being so proportioned in size that when supplied with directV current from the same source the two magnets are equally but oppositely ma netized.

6. In a te ephone receiver, in combination, a diaphragm, an actuating magnet having 'a soft iron'core and two'energizlng coils connected in parallel relation located on each side of the diaphragm, the two coils of fme of the ma nets being similarly wound and the two coil-s of the other magnet being 0ppositely wound, and the several coils being so proportioned in size that when supplied with direct current from the same source `'the two magnets are equally-but oppositely voice currents while the other coil of each' magnet possesses impedance to restrict thev low of voice currents, the two coils adapted to be traversed by voice currents being op- LOUIS W; CARROLL. Witnesses:l

GHARLEs B. GILLsoN,

E. M. KLATCHER, 

